1. Field of the Invention
The invention related to a method for clarifying any sewage containing decomposable solid matter by means of continuous sewage-treatment in physical processing stages equipped with assigned solid matter separators in the form of a coarse-matter separator, a fine-matter separator as well as a downstream heavy medium separator with following flotation-stages, from which solid-matter foam that has been developed by using impact mixing valves or gas-water mixers, is separated. The invention also relates to a device to performing the method and an aerator for the sewage.
The known methods for sewage clarification which apply several clarification processes in sequence, are mainly executed at stationary plants. The structural configuration of such plants is costly and they have a high space requirement as well as a dependence on steady solid matter and load factors. Transportable devices generally are based on a filtering technique extended by either chemical or biological treatment. Therefore, the planned use thereof is limited to one type of sewage. Each filtering technology, operating individually or as the main emphasis, causes an increase of contamination in the neglected part. Physical filtering techniques dissolve additional matter by abrasion or turbulent flow. Biological clearing stages cause an increase of physical water contamination in the form of dead and living substances such as biomasses, sewage fungi and parasites. Chemical clearing through additives, after a previous elimination of all other polluting materials to the greatest possible extent, causes an extraordinary quantity of highly contaminated waste.
When purposefully used in special ranges for special sewage and operated as required, each method achieves good results. However, a satisfactory total clearing, especially of different types of sewage, in accordance with regulations regarding clarified-water effluence, can not be achieved that way.